Metal rolling

ABSTRACT

Lubricating and cooling the work roll surfaces and metal rolled during hot rolling is effected by applying to roll surfaces and metal a water containing a dispersed phase of mineral oil and film strength and friction controlling additive.

United States Patent Bridenbaugh et al.

METAL ROLLING Inventors: Peter R. Bridenbaugh, Greensburg, Pa.; Albert J. Kovolick, Newburgh, lnd.; Sidney A. Paradee, Sun City Center, Fla.

Assignee: Aluminum Company of America,

Pittsburgh, Pa.

Filed: Aug. 12, 1974 Appl. No.: 496,718

Related US. Application Data Continuation-impart of Ser. No. 335,019, Feb. 23, 1973, and a continuation-in-part of Ser. No. 313,564, Dec. 8, 1972, abandoned.

US. Cl 72/42; 72/236 Int. Cl. B21B 27/10; B21B 45/02 Field of Search 72/41, 42, 43, 44, 45,

References Cited UNITED STATES PATENTS 12/1938 l-lurtt et al. 72/43 [4 1 Oct. 14, 1975 2,914,975 12/ 1959 Cavanaugh et al. 72/42 3,150,548 9/1964 Roberts 72/42 3,192,752 7/1965 Dowd et al. 72/45 3,505,844 4/1970 McLean 72/42 3,605,473 9/1971 Lyon et a1... 72/42 X 3,613,425 10/1971 Roberts l 72/202 3,709,012 l/1973 Larsonneor 72/43 X FOREIGN PATENTS OR APPLICATIONS 988,073 4/1965 United Kingdom Primary ExaminerC. W. Lanham Assistant ExaminerE. M. Combs Attorney, Agent, or FirmEdward B. Foote, Esq.

[57] ABSTRACT Lubricating and cooling the work roll surfaces and metal rolled duringv hot rolling is effected by applying to roll surfaces and metal a water containing a dispersed phase of mineral oil and film strength and friction controlling additive.

4 Claims, 1 Drawing Figure Oct. 14, 1575 U.S. Patent METAL ROLLING This application is a continuation-in-part of our U.S. applications Ser. No. 313,564, filed on Dec. 8, 1972, and Ser. No. 335,019, filed on Feb. 23, 1973, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to the rolling of metals, and relates particularly to hot rolling metal while supplying coolant and lubricant to the metal being rolled and to the work rolls employed.

It is common practice in rolling metals to lubricate and cool the metal and the work rolls of the rolling mill by application of a liquid to the metal or to the work rolls, or both. Various liquids have been proposed and used for that purpose, such as water, oils, and water-inoil mixtures or emulsions, with or without supplemental additives, such as fats, fatty acids, alcohols and derivatives thereof. Likewise, various procedures and techniques for applying such liquids to the metal being rolled and to the work roll surfaces have been taught by the prior art, such as for example U.S. Pat. Nos. 2,914,974, 2,9l4,975, 3,192,752, 3,505,844 and Canadian Pat. No. 256,796.

The nature and qualities of the liquid employed, and the procedures used in applying the liquid to the roll surfaces and the metal being rolled, are important factors in securing rolled products of desired characteristics, such as uniformity of metal thickness and surface appearance, as well as maintenance of temperatures best suited to achieving economically the desired reduction in metal thickness.

It is the object of this invention to provide an improved cooling and lubricating procedure for use in hot rolling metal.

STATEMENT OF THE INVENTION In accordance with the present invention, in hot rolling metals the desired lubricating of the metal passing through the work rolls of the rolling mill, and the cooling and lubrication of the work roll surfaces which effect the rolling of the metal, is effected by applying to the metal entering the work rolls, and to the surface of the work rolls on the metal exit side of those rolls, a dispersion consisting of water containing a dispersed phase consisting of mineral oil and at least one component for imparting lubricant film strength and controlling friction.

The aforesaid dispersed phase constitutes O.55% by weight of the dispersion, preferably 0.5-3%, and 50-80% by weight of the dispersed phase consists of mineral oil. In general, mixed base oils in which naphthenics predominate over paraffins, and which have a viscosity of 65-350 Saybolt Seconds Universal at 100F are preferred. The remainder of the dispersed phase consists of known additives for imparting film strength and controlling friction in metal rolling, such as glycol and glycerol esters of fatty acids (e.g-. tall oil, safflower oil, soybean oil and cotton seed oil), and dibasic acids and G1 to C-8 esters thereof, or monobasic fatty acids and esters thereof (eg stearic acid, butyl stearate, and oleic acid). In addition, rust inhibitors, such as alkyl amine phosphates, and wear inhibitors such as tricresyl phosphate, may be included as part of the dispersed phase, if desired. It is characteristic of the dispersions described above for use in carrying out the invention that the dispersed phase separates quickly from the water, as demonstrated by the fact that when the dispersed phase components and water have been mixed together thoroughly at F, and the resultant mixture is then held at 150F without stirring or agitation, 25-100% by volume of the dispersed phase separates from the water within 30 minutes. Dispersions meeting the latter test are referred to herein as dispersions which are characterized in that the dispersed phase therein is quickly separable from the water. The dispersions characteristic of rapid separability of the dispersed phase and water makes feasible the feature described below of providing a higher concentration of dispersed phase in the re-cycled lubricant fed to the metal entering the work rolls than is present in recycled lubricant fed to the metal exit side of the rolls. The above-mentioned rapid separability of the dispersed phase distinguishes the dispersions used in our invention from water-base lubricants which contain an emulsifier, for emulsifiers inhibit separation of dispersed phases from the water.

THE DRAWING The invention will be more particularly described in connection with the accompanying drawing, which is a diagrammatic view of a rolling mill and auxiliary apparatus for supplying the dispersion mentioned above.

In the drawing a conventional four-high roll stand 1 consists of opposed work rolls 2 supported by backing rolls 3. Metal strip 4 is fed between the rolls 2 in the direction indicated by an arrow to reduce it in thickness to the desired degree. To cool and lubricate the rolls 2, and to lubricate the strip 4, the above-mentioned dispersion is directed through the nozzles 5 directly onto the strip itself or, indirectly by spraying it onto the rolls 2 on the metal inlet side thereof.

Simultaneously the dispersion is sprayed on the rolls 2 on the metal exit side thereof through nozzles 5a, the dispersion corresponding in composition to that applied on the metal entry side as described above, except that it is a feature of the invention that the concentration of the dispersed phase applied on the metal exit side of the rolls 2 is lower than it is in the dispersion applied on the metal entry side of the rolls. Rolling debris such as particles of metal, metal oxides, and dirt is preferentially wetted by the dispersed phase components. Since the dispersion is characterized by the dispersed phase being quickly separable therefrom, having a larger concentration of the dispersed phase in the. dispersion supplied to the metal entry side of the rolls results in a larger amount of separated dispersed phase components being available for scavenging rolling debris from the rolls and metal than would be the case if the concentration of dispersed phase in the dispersion applied to the metal entry side of the rolls were the same as the concentration of dispersed phase in the dis persion applied at the metal exit side of the rolls, while also avoiding providing more dispersed phase than is necessary or desirable in the dispersion applied to the metal exit side of the rolls. Thus, providing a higher concentration of the dispersed phase in the dispersion applied at the metal entry side of the rolls results in scavenging of rolling debris from the metal and from the work rolls to best advantage from the standpoints of economy of operation and uniformity and surface appearance of the rolled metal. Preferably the concentration of the dispersed phase in the dispersion supplied via nozzles 5 is 0. l-O.3% by weight higher than in the dispersion supplied via nozzles 5a.

From the strip 4 and the rolls 2 the dispersion drains into a sump 6 and thence through a filter 7 for removal of rolling debris and the like and into a supply tank 8, from which it is re-circulated to the nozzles 5 and 5a as described below.

Dispersion from the tank 8 is pumped to the nozzles via pump 9, supply line 10, and the supply line extension 10a. A further portion of the dispersion in tank 8 is pumped via pump 11 to a separation tank 12, where the water therein is separated from the dispersed phase and is pumped back to the tank 8 by the pump 13. The composition of the dispersion being such that the dispersed phase separates rapidly from the water, separation of the dispersed phase from water in tank 12 occurs sufficiently quickly for the system to operate in an economically practical way. The dispersed phase which has been thus separated from the water in tank 12 is pumped via pump 14 to a storage tank 15, from which it is pumped via pump 16 into supply line extension 10a in sufficient amount to increase to the desired degree the concentration of the dispersed phase in the liquid fed to the nozzles 5. As a result, the dispersion fed to the nozzles 5 contains a higher concentration of the dispersed phase than does the dispersion fed to the nozzles 5a. Concentrations of dispersed phase in the dispersion fed to the metal entry side of the rolls higher than 5% by weight are undesirable, since such concentrations result in undue slippage of the rolls on the metal being rolled.

A preferred dispersion for use in accordance with this invention contains 0.67% of mineral oil (100 seconds SSU/lOOF), 0.2% methyl tallowate, 0.1% of isostearic acid, and 0.02% of tricresyl phosphate (the above percentages being by weight), the balance being water having a pH of 4-7. When those components are mixed thoroughly at 150F and the resultant dispersion is then held at 150F without stirring or agitation, by volume of the dispersed phase separates from the water in minutes.

Although the invention has been described and illustrated above with reference to rolling metal in a single stand rolling mill, it will be understood that it is also applicable to rolling operations in multi-stand, tandem mills.

We claim:

1. In hot rolling metal between work rolls, the improvement comprising applying to the metal entering the work rolls, and to the work rolls on the metal exit side thereof, a dispersion composed of water and 0.55% by weight of a dispersed phase consisting of mineral oil and at least one component for imparting film strength and controlling friction, the mineral oil constituting 5080% by weight of the said dispersed phase, the said dispersion being characterized in that the dispersed phase therein is quickly separable from the water, the concentration of the said dispersed phase in the dispersion applied to the metal entering the work rolls being higher than the concentration of the dispersed phase in the dispersion applied to the work rolls on the metal exit side thereof.

2. The method in accordance with claim 1, in which the concentration of the dispersed phase is O.53% by weight.

3. The method in accordance with claim 1, in which the concentration of the dispersed phase in the dispersion applied to the metal entering the work rolls is O. l-O.3% by weight higher than the concentration of the dispersed phase in the dispersion applied to the work rolls on the metal exit side thereof.

4. The method in accordance with claim 1, in which the said dispersions drain from the said metal and the said work rolls and are collected and then re-circulated to the said metal and work rolls, the said higher concentration of dispersed phase in the dispersion applied to the metal on the metal entry side of the work rolls being effected by separating dispersed phase from water in a portion of the collected dispersion, and introducing the said separated dispersed phase into the dispersion re-circulated to the metal on the metal entry side of the work rolls. 

1. In hot rolling metal between work rolls, the improvement comprising applying to the metal entering the work rolls, and to the work rolls on the metal exit side thereof, a dispersion composed of water and 0.5-5% by weight of a dispersed phase consisting of mineral oil and at least one component for imparting film strength and controlling friction, the mineral oil constituting 50-80% by weight of the said dispersed phase, the said dispersion being characterized in that the dispersed phase therein is quickly separable from the water, the concentration of the said dispersed phase in the dispersion applied to the metal entering the work rolls being higher than the concentration of the dispersed phase in the dispersion applied to the work rolls on the metal exit side thereof.
 2. The method in accordance with claim 1, in which the concentration of the dispersed phase is 0.5-3% by weight.
 3. The method in accordance with claim 1, in which the concentration of the dispersed phase in the dispersion applied to the metal entering the work rolls is 0.1-0.3% by weight higher than the concentration of the dispersed phase in the dispersion applied to the work rolls on the metal exit side thereof.
 4. The method in accordance with claim 1, in which the said dispersions drain from the said metal and the said work rolls and are collected and then re-circulated to the said metal and work rolls, the said higher concentration of dispersed phase in the dispersion applied to thE metal on the metal entry side of the work rolls being effected by separating dispersed phase from water in a portion of the collected dispersion, and introducing the said separated dispersed phase into the dispersion re-circulated to the metal on the metal entry side of the work rolls. 